A navigation system performs travel guidance for enabling a user to easily and quickly reach the selected destination. A typical example is a vehicle navigation system where a vehicle is equipped with a navigation function to guide a driver to a destination through a calculated route. Such a navigation system detects the position of the user's vehicle, and reads out map data pertaining to an area at the current vehicle position from a data storage medium, for example, a CD-ROM (compact disc read-only memory), a DVD (digital versatile disc), or a hard disc. Typically, the navigation system displays a map image on a monitor screen while superimposing thereon a mark representing the current location of the user. At an intersection on the calculated route, the navigation system notifies the user which direction to turn at the intersection, if necessary.
Such a navigation system is designed to display a map image and various types of icons and map elements on the screen so that the user is able to obtain various information through graphical representations on the screen. Typically, icons related to types of business such as POI (point of interest) icons will be displayed when a scale factor of the map image on the screen becomes smaller than a predetermined value. Such POI icons will be displayed at locations on the map image that correspond to the actual business locations of the entities represented by the icons.
Typically, such POI icons can be classified into generic icons and brand icons where generic icons represent categories or types of business such as restaurant, gas station, banks, etc., while brand icons represent individual businesses. A generic icon will not differentiate a individual business from the others in the same category but simply indicates the category of the POIs. Thus, fast food restaurants such as “McDonald”, “Burger King”, “Pizza Hut”, etc., are represented by the same generic icon indicting the category of restaurant. However, a brand icon will differentiate an individual business from the other, thus, for example, a brand icon of “McDonald” will distinguish the “McDonald” restaurant from the other restaurants.
However, not all brand icons are instantly recognizable by every one. Although national brand icons (icons that are used throughout the country) can be recognized by most users, there are brand icons that can only be recognized by users familiar with a particular local area. For instance, some restaurant chains operate locally, such as only in the western states such as California, Nevada and Arizona, but not in the other states. In such a case, a brand icon, such as a restaurant logo, that is easily recognizable to many users in California may not be easily recognizable to users from the other states such as from New York.
FIGS. 1A and 1B are schematic diagrams showing map images on the screen of the navigation system that illustrate a plurality of icons including generic icons as well as brand icons. In the example of FIG. 1A, the screen shows generic icons 27d for restaurants, a generic icon 27e for a hotel/lodging, generic icons 27f for gas stations, as well as a brand icon 27a for a restaurant, brand icons 27b for gas stations, and another brand icon 27c for a restaurant.
In the example of FIG. 1B, in addition to the same generic icons and brand icons of FIG. 1A, it also includes brand icons 27g for restaurants. In this example, the brand icons 27a and 27c are national brand icons, which are assumed to be well known and used throughout the country. In contrast, it is assumed that the brand icon 27g is a local brand icon which is known and used only within a particular local area. Thus, the users who are not familiar with the particular local area are not likely to recognize the local brand icons 27g. 
Brand icons are not very useful if they do not provide the function of indicating what kinds of business they represent. Thus, it is desired to develop a means through which the users not familiar with a particular brand icon is able to judge or guess a category of business the brand icon represents. Especially, it is desired a new method and apparatus for a navigation system that can achieve such a function through graphic representations on the screen.